xsk: relax UMEM headroom alignment

This patch removes the 64B alignment of the UMEM headroom. There is
really no reason for it, and having a headroom less than 64B should be
valid.

Fixes: c0c77d8 ("xsk: add user memory registration support sockopt")
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

net/xdp/xdp_umem.c

@@ -383,8 +383,6 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
 			return -EINVAL;
 	}
 
-	headroom = ALIGN(headroom, 64);
-
 	size_chk = chunk_size - headroom - XDP_PACKET_HEADROOM;
 	if (size_chk < 0)
 		return -EINVAL;